Assignment 2
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Pig Latin

In this assignment, you'll be writing a translator from English to Pig Latin.

Note: The point of this exercise is to learn how to implement a subclass of class Reader, and to use that subclass in a couple of typical applications .   It is certainly possible to implement this not using a subclass of Reader, but that will make things harder to do when you get to use the resulting code in the applications.
Also, as with all such assignments, I expect you to implement a general solution, not one that is merely focused on the applications that are used in this assignment.  I expect you to write a solution that could be used by your "customers" in a general way;   that is, you or your "customer" should be able to simply use the resulting class without any need to change it for a particular application.  In the real world, this is what you'll be expected to do, so it's a good idea to get used to it right now!


Pig Latin is a word game usually played by children. They love to become proficient at it, because a lot of adults can't understand what they're saying when they converse in Pig Latin. If you have any children, you'll understand the motivation.

There are a number of dialects of Pig Latin, but here's one with some simple rules:

  1. Take any passage of English
  2. Break the passage up into individual words and punctuation
  3. Each word is transformed as follows:
    • If the word begins with a vowel ('a', 'e', 'i', 'o', or 'u') append "yay" to the word.
      For example: "am" becomes "amyay", 'I' becomes "Iyay", "aardvaark" becomes "aardvaarkyay", etc.
    • If the word begins with a consonant (any letter that is not a vowel), find the first vowel in the word, divide the word just before that vowel, swap the two parts of the word, and append "ay" to the resulting word. If the original word had its first letter capitalized, make sure that that letter is not capitalized after the word is divided, and ensure that the first letter of the resulting word is capitalized.
      For example, "string" becomes "ingstray", "Latin" becomes "Atinlay" (note the capitalization), "student" becomes "udentstay", "professor" becomes "ofessorpray", etc.
    • If the word has no vowels (we count 'y' as a consonant, here), append "yay" to it.
      For example, "my" becomes "myyay", "pry" becomes "pryyay".
  4. Punctuation is not changed by the translation process.  
    In particular, treat apostrophe (') and double-quote (") characters as word separators, not as part of a word.   The apostrophe is used in contractions, such as "can't", as well as in other uses, such as "his 'notorious' aunt", so it's quite difficult to distinguish between these usages.  Since this assignment is focused on how to write a subclass of Reader, we'll take the easy way out, by ignoring the problem..
  5. Put the translated words and punctuation back into the same order as their corresponding original words and punctuation.
  6. The whitespace (space characters, tab characters, newlines, etc.) between words should be maintained.
  7. If the first letter of an untranslated word is capitalized, then the first letter of the translated word should also be capitalized.  If the original first letter is moved during the word's translation so that it is no longer the first letter of the word, then it should be lowercased.

Note:  Since you're going to implement this as subclass of Reader, think in terms of treating the input as a stream that potentially has no end.   Do not simply read until you're read everything in the stream, and only then return some translated output.   If you did that on a very long (or infinite stream), you'd soon run out of memory!  Instead, translate a word at a time, which involves a relatively small amount of read-ahead on the input stream.   This illustrates the whole concept of a stream -- it is something that allows processing "as the stream flows by", rather than blocking the stream (which we all know can cause flooding).

For example, here is an applet that can transform a web site into the Pig Latin equivalent. Just type in your favorite web site address and click on the "Go!" button. Note that not all web sites are amenable to such translation; ones that are include:

  • Try your own favorite!

Did you forget to enable Java in your browser?

Below is a Java applet that uses the above algorithm to translate from English to Pig Latin. Enter your English text in the upper (white) text area, and then click on the Translate button, and you'll see the Pig Latin equivalent in the lower (grey) text area.

Did you forget to enable Java in your browser?

What To Do

  1. Write a Reader Class to perform the English to Pig Latin Translation

(I called my class EnglishToPigLatinReader.)

The class should:

  • Be placed in package pigLatin
  • Extend from class PushbackReader
  • Have a constructor of the form:
public EnglishToPigLatinReader(Reader in)

so that the class may be used as a conventional Reader class, with the usual nesting capabilities:

new BufferedReader( 
	new EnglishToPigLatinReader( 
		new FileReader(input) )
  • Override the Reader methods:
public int read() 
  throws IOException
public int read(char[] cbuf, int off, int len) 
  throws IOException
  • Add any private methods necessary, based on your particular implementation.
  • Have a main() method that tests the class' capabilities.

Some hints, based on my implementation experiences:

  • I tried using StreamTokenizer, but found that it was overkill. Also it did not allow me to maintain the whitespace characters
  • I thought about using StringTokenizer, but also felt that it was overkill.
  • I found it useful to allow characters to occasionally be pushed back onto the input, which is why I extended from PushbackReader.
  • I also found it useful to encapsulate the translation of a single English word to Pig Latin inside a private method (which I called latinize()).

For what it's worth, my implementation of this class was 263 lines long, including comments and (lots of) blank lines.

  1. Write an Application that, given a file containing English text, outputs the translated text to standard output.  

    The application must use the EnglishToPigLatinReader class you implemented above.   

    Note: If you implemented the EnglishToPigLatinReader class correctly, you should not have to change the EnglishToPigLatinReader class in the slightest way.   If you find you have to modify the EnglishToPigLatinReader class in any way, go back to part A, and implement it properly, then try again.

  2. Write an Application to Emulate the above Translation Applet

The application must use the EnglishToPigLatinReader class you implemented above.  If you implemented the EnglishToPigLatinReader class correctly, you should not have to change the EnglishToPigLatinReader class in the slightest way.

Note: My applet is a mere 87 lines long, including comments and empty lines, so it's not a huge effort.

The page was last updated February 19, 2008